1. Field of the Invention
This invention relates to trim-tilt devices for marine propulsion devices.
2. Description of the Prior Art
In a particularly small boat such as a motorboat, an engine and screw are integrally formed to be a propulsion device and this propulsion device is fitted to the hull so as to be rotatable in a vertical plane. That is to say, at the time of the operation of the propulsion device, a trimming operation for setting the screw at a proper angle in response to the mounted weight will be made so that a desired speed may be obtained and, in the case of pulling the hull up out of the water onto the land, a tilting operation for lifting the screw above the water surface is made to prevent the screw from being broken. U.S. Pat. No. 3,962,955 describes this type of device. However, in this patent, separate oil pressure cylinders are used for the trimming operation and tilting operation and therefore the device is complicated, large and heavy.